In VitroEffects of Thyrotropin on Certain Metabolic Activities of Isolated Thyroid Cells1

Abstract

The synthesis of thyroxine, transport of iodide, oxidation of glucose, and uptake of α-aminoisobutyrate were observed in isolated bovine thyroid cells. TSH added at concentrations as low as 10^-4 U/ml stimulated thyroxine synthesis and the uptake of α-aminoisobutyrate. The conversion of glucose- l-^l4C to ^l4CO₂ was stimulated by 0.2 U/ml of TSH. Iodide concentrating activity, as expressed in terms of intracellular to extracellular iodide concentration ratios, was generally depressed by added TSH. These findings provide further support for the view that TSH may have separate and independent stimulatory actions on a number of metabolic pathways in the thyroid cell. (Endocrinology75: 527, 1964)